A couple years ago, I remember reading to the kids about Commodore Matthew C. Perry’s visit to Japan in 1854, and how it opened Japan to trade with the US for the first time. But I didn’t realize that the word tycoon came directly from this visit!
During Perry’s meetings, the shogun’s supporters wanted to make it very clear to the guests that the shogun was actually more important than the emperor when it came to making decisions. So they called him taikun, which is literally “great prince”–(ta, great + kiun, prince). Perry brought the word home with him, and it apparently quickly caught on.
During Lincoln’s term as president, his cabinet members began to affectionately refer to him as the tycoon (the Americanized spelling of the word). This nudged the meaning from “great prince” to “important person.” Only after World War One did the meaning travel a bit more to mean “wealthy and powerful businessman.”